var fetchUrl = function (url, body, cb) {
    var xhr = new XMLHttpRequest()
    xhr.open('POST', url, true)
    xhr.withCredentials = true
    xhr.setRequestHeader('Content-Type', 'application/json;charset=UTF-8')
    if (window.localStorage && typeof window.localStorage.getItem === 'function') {
        var memberId = window.localStorage.getItem('syllableSession')
        if (memberId) {
            xhr.setRequestHeader('Authorization', 'Bearer ' + memberId)
        }
    }
    xhr.onload = function () {
        cb(null, this.responseText)
    }
    xhr.onerror = function () {
        cb(this.response)
    }
    xhr.send(JSON.stringify(body))
}

var getCurrentLanguage = function () {
    var lang
    if (window.localStorage && typeof window.localStorage.getItem === 'function') {
        lang = window.localStorage.getItem('currentLang')
    }
    return lang || 'en'
}

var getClientSettings = function () {
    try {
        var cookies = decodeURIComponent(document.cookie).split('; ')
        var clientSettingsCookie = (cookies.filter(function (c) {
            return c.indexOf('web-client-settings') === 0
        }) || [])[0]
        if (!clientSettingsCookie) {
            return {}
        }
        var clientSettingsStr = clientSettingsCookie
            .replace('web-client-settings=', '')
            .replace(/%20/g, ' ')
        return JSON.parse(clientSettingsStr)
    } catch (err) {
        console.warn('error getting client settings: ', err)
        return {}
    }
}

var fetchSettings = function (id, cb) {
    var payload = {
        id: id,
        metadata: {
            title: window.document.title,
            url: window.location.href,
            referrer: window.document.referrer,
            mobile: false,
            lang: getCurrentLanguage(),
        },
    }

    var clientSettings = getClientSettings()
    if (clientSettings.id === id) {
        payload.client_settings = {
            shim_version: clientSettings.shim_version,
            mode: clientSettings.mode,
        }
    }

    fetchUrl('https://winston-production.syllable.ai/get_settings_web', payload, cb)
}

var injectShim = function (shimUrl) {
    var script = document.createElement('script')
    script.async = true
    script.src = shimUrl
    document.head.appendChild(script)
}

var onReceiveSettings = function (error, settings) {
    if (error) {
        return
    }
    if (!settings) {
        return
    }
    var parsed
    try {
        parsed = JSON.parse(settings)
    } catch (err) {
        parsed = null
    }
    if (!parsed || typeof parsed !== 'object' || parsed.listening_mode) {
        return
    }
    if (parsed.full_app_title && document.title === 'Web Assistant') {
        document.title = parsed.full_app_title
    }
    window.Syllable = { q: [] }
    window.syllableSettings = parsed
    var memberId
    if (window.parent.localStorage && typeof window.parent.localStorage.getItem === 'function') {
        memberId = window.parent.localStorage.getItem('syllableSession')
    }
    if (memberId) {
        window.syllableSettings.member_id = memberId
    }
    injectShim(parsed.shim_url)
}

var loadSettings = function () {
    var scriptSrc = document.getElementById('syllable-tag').src
    var idx = scriptSrc.indexOf('?id=')
    var tagId = idx > -1 ? scriptSrc.substr(idx + 4) : undefined
    fetchSettings(tagId, onReceiveSettings)
}

if (window.document.readyState === 'loading') {
    window.document.addEventListener('DOMContentLoaded', loadSettings)
} else {
    loadSettings()
}